If he says it for the same reason I'd say it it is because in my experience salespeople tend to provide "aggressive" estimates (e.g. You said 10 days, that's almost the same as 5 days, isn't it?) if they think they have better chances to make a sale doing this. So, maybe, cutting into their share would help to deliver a (IMHO) very important message: There are deals which aren't worth it.